| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 489 March 17, 2015 | aceska@telus.net | Victoria, B.C. |
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For the accompanying plates see: http://mpb.ou.edu/ben/489/ben489_sporormiella.pdf
Palynology was introduced into the study of postglacial changes in climate and vegetation by von Post in 1916. Since then it has been used for tracking and mapping vegetation (and climate) changes of the last ca. 15,000 years. The postglacial period is a complex era with dramatic climatic changes, human migration, animal extinctions, soil development, and sea level changes, to mention just the main issues important for understanding the period. People who study this era are typically "polyhistors," experts in all disciplines that deal with this era.
Mycology entered into this picture much later.
In 1975, Davis introduced the coprophilous ascomycete Sporormiella australis into palynology, in order to assess a history of the grazing pressure around Wildcat Lake, Whitman County, Washington (Davis, 1975; Davis et al. 1977). Later he applied this technique for tracking the megafauna decline in southern Idaho after the last glaciations (Davis, 1981). Prof. Jack Rogers, Washington State University mycologist, played an important role in selecting Sporormiella as a marker to estimate intensity of grazing. (See his note below.)
Sporormiella is an ascomycete fungus found only on the dung of herbivores, and commonly on the dung of domestic herbivores and extinct and living megaherbivores. The genus is widespread in sub-boreal and temperate regions of the world. Sporormiella spores are born in sclerotia on the surface of drying dung, and are spread passively to nearby vegetation, where they are ingested and later germinate in shed feces to complete the fungus' life cycle. The spores of Sproromiella australis have characteristic features: their ascospores are three septate with four dark segments; each segment has characteristic germ-slits. The spores can be easily recognized in palynological preparations and this enables their use in paleoecology as a proxy for the abundance of grazing mammals. The low height of spore release precludes efficient long-distance dispersal, but mycologists have seen Sporormiella spores in airborne (vacuum trap) samples from Tucson, Arizona, and in fresh snow samples from the Sierra Nevada. Ordinarily, we expect Sporormiella spore abundances to be high only near accumulations of herbivore feces.
Sporormiella appeared to be ideal for tracking mammals in palynological sediments; it is a fungus with cosmopolitan distribution, its spores are relatively well preserved, and they are also easily identifiable. This technique has enabled tracking the megafauna decline in various parts of the world: Madagascar (Burney et al. 2004), Australia (Cook et al. 2011, Rule et al. 2012), North America (Gill et al. 2013, van Geel et al. 2013), Europe or Eurasia (Jamrichova et al. 2012). Most of these articles show that the decline of megafauna coincides with major climate changes, as well as with increased human population and human migration.
My involvement with Dr. Davis and fungal spores occurred when he consulted me about a research project that was, approximately, as follows. There was interest in determining the history of large animal activity around a dying eastern Washington lake that was filling with various materials. Davis, who was an anthropology student oriented toward pollen, wanted to know if there were other potential markers in the strata of the filling lake bottom that would indicate when and if large animals had drunk from lake over time. At that time there was interest in the possibility that bison had at one time roamed eastern Washington, despite the fact that Nez Perce and other regional Indians had annual forays to hunt bison in territories east of this region. I suggested that large animals that drank from the lake would also defecate in it or on its shores. Knowing that dung of all large animals extant in this area have a mycobiota of ascomycetous fungi with dark heavily melanized ascospores, I suggested that Davis search the various layers for dark spores. Among the ascomycetous genera that I suggested was Sporormiella (formerly Sporormia, which is now used in a much more restricted sense). Davis was indeed able to use ascospores of Sporormiella species in his studies, published his Washington State University work and built a distinguished career on more or less similar studies. My formal involvement with Dr. Davis ceased when he left Washington State University [in 1975].
Bladderworts (Utricularia spp.) are Montana's most common carnivorous plants. There are nearly 20 species of Utricularia in North America north of Mexico. Of the five species occurring in western North America, Utricularia ochroleuca is the least common. Over 100 years ago this plant was collected in Yellowstone National Park (Martin s.n., POM). The specimen label lists the state as Montana, but I believe it is more likely from Wyoming because a recent floristic study (Hellquist et al. 2014) found U. ochroleuca several times in Wyoming but not Montana. The first bona fide collection from Montana was made in a rich fen just east of Glacier National Park on the Blackfeet Indian Reservation in 2012 by Tara Luna, a botanist who lives on the Reservation, and me. Adolf Ceska tentatively identified our plants as U. ochroleuca, and Garrett Crow, author of the as yet unpublished Flora of North America treatment, confirmed his determination. Connelly Fen, where we found U. ochroleuca, is on the plains well east of the mountains, harbors several other plants considered rare in the state, and is listed as an Important Plant Area by the Montana Native Plant Society (http://www.mtnativeplants.org/Important%20Plant%20Areas). A second location for Utricularia ochroleuca in Montana was discovered just this past year in another calcareous fen halfway between the Blackfeet Reservation and Yellowstone Park. Again Garrett Crow verified the determination. This fen complex also supports populations of other rare plants, such as Thalictrum alpinum and Primula incana.
Utricularia ochroleuca has not been observed to flower in Montana. Without flowers U. ochroleuca can be mistaken for U. minor; however, U. ochroleuca has setose leaf margins and U. minor does not. Utricularia intermedia is also similar but it has bladders only on white, leafless branches, while U. ochroleuca has bladders on both leafless and leafy branches. However, the best way to distinguish among the three species is by microscopic examination of the hair-like glands on the inside of the bladders called quadrifids. Garrett Crow performed the necessary dissections and provided me with photographs of the quadrifids of the three species in question. The shape of and the angle between the arms of the quadrafids are diagnostic.
More than one-third of all species of carnivorous plants on earth are bladderworts, and species of Utricularia occur from the tropics into the arctic. Some species of these rootless plants grow in mud or even as epiphytes in rain-forest trees, but most, like Montana's four species, are aquatic. They all produce bladder-like traps with doors that open and close. Touching the hairs around the door causes it to open and suck in whatever is just outside. The traps are capable of capturing small animals and absorbing nutrients from them. But there's more to the story; it seems that some bladderworts may be more gardener than carnivore.
Several years ago researchers at the University of Wisconsin made a confusing discovery. They found that Utricularia vulgaris (= U. macrorhiza, our most common species) grown in water with a high density of invertebrates (potential prey) did not respond by producing more traps. However, they did produce more traps when the water was higher in nutrients. Apparently bladderworts produce traps for a reason other than just capturing prey, a reason related to the fertility of their surroundings.
Recently Jennifer Richards at Florida International University made some observations that may help explain the Wisconsin findings. Richards examined 1,400 traps from Utricularia purpurea in the Everglades. She found that 63% had something in them. Of these only 8% contained dead prey items, but all contained algae, diatoms or other photosynthetic organisms. I have made the same observation here in Montana. All the old bladders have green stuff in them, but it's devilishly hard to show people a trap with a dead bug in it.
Richards proposes that bladderwort bladders act not so much as traps but as tiny microcosms, absorbing the waste products produced by their photosynthetic and bacterial occupants. This hypothesis may also explain the Wisconsin finding that bladderworts produce more traps in nutrient-rich water but not in prey-rich water. Algae grow better in nutrient-rich water, so a bladderwort's captive algae gardens will be more productive. In addition the bladders may also absorb nutrients directly from the water. This is an unusual strategy to compensate for a lack of nutrient-absorbing roots, but it is not unique.
Certain tropical epiphytes called tank bromeliads obtain nutrients in a similar fashion. These plants live in tree canopies and are unable to absorb nutrients through their roots. Instead they hold water at the base of their leaves. These miniature "ponds" support all manner of aquatic life including mosquito larvae and even frogs. The bromeliads absorb the waste products from these little ecosystems directly into specialized cells at the base of the leaves.
More research needs to be done to prove that algal waste products are contributing to bladderwort nutrition. Still, it seems likely that bladderworts are really omnivores, obtaining more of what they need from gardening than from carnivory. It's just another case of "whatever works." So it looks like I lost my cool story about bladderwort carnivory. But that's okay because the real story is even more fascinating.
The application of the name Amelanchier lamarckii Schroeder to a widely cultivated and wild species of Amelanchier in North America and Europe has been questioned. The taxon, best treated as a species, is distinguished by its often reddish, acuminate, moderately pubescent leaves with relatively small teeth and glabrous ovaries.
In 1968 Schroeder provided the replacement name, Amelanchier lamarckii for Lamarck's (1783, p. 84) Crataegus racemosa to be applied to a North American taxon that had become widespread in Europe. Schroeder's new name would have been a "disadvantageous nomenclatural change" (ICN 56.1) if this taxon was already recognized in North America. However, regarding the three naturalized taxa of Amelanchier in Europe, including A. lamarckii, Schroeder noted that "none of them is known as a distinct species in North America", but that was not the case. Amelanchier lamarckii, as Amelanchier intermedia Spach (1834), was treated as a distinct species by Fernald (1950) and earlier by Wiegand (1920). After Schroeder's 1968 publication it was again referred to A. intermedia in North America (e.g. Cinq-Mars 1971, Scoggan 1978, Campbell & Doucette 2010). It is true however, that the name A. intermedia had been variously treated as a synonym in some North American literature. Jones (1946) for example had placed it with A. canadensis and Cruise (1964) promoted the idea of it being a microspecies or a hybrid. While A. lamarckii was perhaps a "disadvantageous nomenclatural change" in 1968, it is unlikely that it would be deemed sufficiently disadvantageous today to warrant rejection in favour of Amelanchier intermedia.
Some other aspects of the name Amelanchier lamarckii also warrant consideration. A direct citation of a the type element (ICN 7.10, 12.1) was lacking in the first publication of Schroeder's name, but the neotypes were clearly cited later (Schroeder 1972). Some considered that Lamarck's description of Crataegus racemosa could apply to any of a number of North American species such as Ame;anchier arborea, A. intermedia, A. stolonifera and A. grandiflora, but Schroeder's concept was clear in his later keys (Schroeder 1970, 1972) which he had referred to when A. lamarckii was published in 1968. Another concern has been that Lamarck's reference to a hairy peduncle, presumably at flowering time, does not apply to the taxon in question, and probably not to Schroeder's neotype, thus allowing the neotype to be rejected (ICN 10.5). The relevant question here is how hairy does the peduncle have to be? In fact plants referable to A. lamarckii or A. intermedia are usually essentially glabrous. This does not seem to be quite enough to make A. larmarckii in serious conflict with the protologue because in very early flowering there may be more hair on the peduncle and some variation may also occur. Use of the name Amelanchier intermedia for a plant intermediate between A. laevis and A. canadensis (the plant in question, but not necessarily of hybrid origin based on recent studies) dates back at least to Wiegand in 1912 (p. 124). He clarified the taxon later with a detailed description and species rank (Wiegand 1920, p. 147). Wiegand's views were based to some extent on his evaluation of a specimen at GH identified as A. intermedia by Spach. Fernald's (1950) use of A. intermedia likely has its basis here, for he had great respect for Wiegand 's ability to determine taxa that should be recognized based on his (Wiegand's) extensive field experience, and he had Spach's determination. Most important is that Spach's (1834) type was examined by Schroeder (1972 p. 304) and found it to be "A. arborea" and he did not include A. intermedia Spach in synonymy of A. lamarckii. Spach's description could accommodate A. arborea and there is no particular reason to question Schroeder's evaluation.
With the type of Amelanchier intermedia not being correctly applied to the plant in question and Schroeder's A. lamarckii having gained widespread acceptance in Europe where it is now well established outside of cultivation, the benefits of using this latter name outweigh the disadvantages. Amelanchier intermedia is best treated as a synonym of A. arborea (but A. intermedia sensu Wiegand 1920, Fernald 1950, Cinq-Mars 1971, Scoggan 1978, and Catling & Mitrow 2007 is A. lamarckii). +Amelanchier lamarckii is native in eastern North America, where it is also an escape from cultivation, as well as being established as an escape from cultivation in the Vancouver region of southwestern British Columbia and adjacent Washington.
Addendum
I expected Amelanchier lamarckii to appear in vol. 9 of Flora of North America, but without the details provided above on the application of the name. I have just received the new volume and I find the name A. intermedia is used there (Campbell et al. 2014) for the plant that I am suggesting be referred to A. lamarckii. Although A. lamarckii is not mentioned under A. intermedia on page 660, or elsewhere in the keys and species descriptions, it is mentioned at the end of the genus description on page 648. Here it is indicated that A. lamarckii was described from plants that originated in North America and that plants resembling it have escaped from cultivation in North America. Two references for its escape are Catling & Mitrow (2007) and information on collections by Frank Lomer from the Vancouver region in the UBC herbarium http://www.gbif.org/occurrence/1054803568 .
A new question that arises is whether Amelanchietr lamarckii can be separated from A. intermedia sensu Campbell et al. (2014). Given that the latter is considered to have originated as a hybrid involving A. canadensis and A. laevis (Campbell et al. 2014), which could lead to much variation, it would seem that separating A. lamarckii, considered to be a hybrid confused with A. canadensis and A. laevis by Schroeder (1968, 1970, 1972) would be difficult. If they are the same taxon, A. lamarckii appears to be the appropriate name. The fact that A. intermedia Spach is not listed in synonymy under A. lamarckii by Schroeder is presumably because he examined Spach's type and found it to be A. arborea as outlined above.
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